Pumping mechanism



Nov. 1, 1938. .1. M. BAR-THOLOM-EW PUMPING MECHANISM Filed July 16, 1936fizventbr: h dw'flfiarfalamem a Aw 1 mm,

Patented Nov. 1-, 1938 UNITED STATES PATENT OFFICE,

PUMPING MECHANISM Jess M. Bartholomew, Michigan City, Ind., assignor toSullivan Machinery Company, a corporation of Massachusetts ApplicationJuly 16, 1936, Serial No. 90,946 15 Claims. (01. 230-24) My inventionrelates to an improved automatic system for controlling the starting andoperation of a motor driven compressor.

It is desirable in the operation of motor driven compressors,particularly where a fairly constant and high demand for air exists, tooperate the compressor on the continuous-drive, load-andunload system ofoutput control. It is also desirable to control the compressor duringstarting in such manner that the compressor shall start unloaded. It-isfurther desirable to use the simplest possible controlling equipment toaccomplish the functions mentioned. These same principles of courseapply to pumps handling other fluids than air where the conditions aregenerally the same, and it is perhaps even more important to provide forstarting of a hydraulic pump unloaded than is the case with compressorstor gaseous fluids. P

It is an object of my invention to provide an improved compressorcontrollmgapparatus. .It is another object of my invention to provide animproved compressor controlling apparatus operating to control thevolume of fluid pumped by loading and unloading, while drive ismaintained.

It is 'a. further object of my invention to provide an improved. pumpingsystem having improved means for effecting unloading during starting, as

well as unloaded operation when a predetermined excess of fluid ispumped. Other objects and advantages of the invention will hereinaitermore fully appear.

In the accompanying drawing I have shown for purposes of illustrationone embodiment which my invention may assume in practice.

In this drawing,

Fig. l is a diagrammatic view of a compressor outfit having associatedtherewith an illustrative embodiment of my improved controllingmechanism.

Fig. 2 is a fragmentary view showing a section through an electricallycontrolled pilot mechanism and through the valve mechanismand associatedunloading device for a compressor cylinder.

Referring first to Fig. 1, it will noted. that a motor I drives acompressor 2, herein or the ver-- tical two-cylinder type. Thecompressor discharges fluid through the branch lines 3, 3 to a dischargeline 4. which delivers to a receiver 5, from which the pumped fluid maybe led away to a point of use through a connection 6. Current foroperating the motor i is supplied from lines L, W and L4. and tha motori is herein of the three-phase type. A multi-pole switch I having portit controllable by a valve 44.

concurrently movable contact elements I l I 2, and Ill respectivelycontrolling current flow from the lines L ii. and L is arranged tocontrol the supply to the motor leads M M and M and overload coils O and0 are arranged in the 5 motor leads M and M A plunger l 4 is arranged inposition to be raised by a solenoid l5 upon energization of the latterto close the multi-pole switch 1 and effect motor starting. The overloadcoils O and 0 have re- 10 spectively associated with them plungers 0 and0" arranged so that either or both may actuate an appropriate overloadcontrolled switch It.

The compressor cylinders I1 and 18 are each. provided with individualinlet and discharge 15 valves, and Fig. 2 shows the inlet and dischargevalve mechanism and associated unloading mechanism for one oi thecompressor cylinders. A passage 20 opens into the outer end of one ofthe compressor cylinders. An inlet valve mech- 80 anism 2| controls theadmission of air to the cylinder through the port 20. A discharge valvemechanism 22 controls the discharge of air through the port 20 and to aspace 23 communicating with one of the branch discharge lines 5. 25 Aplunger 24 movable in a cylinder 25, and normally maintained in itsouter position by a spring 2'6, actuates a fork-like member 21 whoseprongs 28 pass through the port openings 29 in the inlet valve mechanisminto engagement with the inlet 80 valve proper 30, and'open the latterand hold the latter unseated, that is, in unloading position, when airis admitted to the outer end oi the cylinder 25. Supply of air to thecylinder 25 is controlled by an electrically operated pilot mechas anism32 which receives a supply of operating pressure through a line 33leading from the receiver 5 and controls the delivery of that operatingpressure through a line 14 to the cylinders 25. This pilot mechanismalso controls the vent- {0 ing of pressure from theline 34 and cylinders25 to a point of escape, as at 55. g

The pilot mechanism comprises a casing 31 having a vent chamber 38, achamber 39 communicating with the cylinder 25, anda supply 45 chamber40. Chambers 38 and 38 are connectible through a valve-seatisurroundedport 4| controlled bya valve .42, and chambers 39 and 4|! areconnectible through a valve-seat-surrounded Valves 42 5c and M are sorelated that but one can be seated at a time. Springs 45 and 45 normallytend to close each of the valves whenever its closure is possible. Bythe provision of arelativel'y heavy plunger 48 operatively connectedwith the valves the interlock switch element 8i coacts in estab-,

42 and 44, the valve 44 may be maintained open -on the other hand,plunger 48 is raised, valve 44 closes port 48 and valve 42 opens port4|, and

accordingly no more air is supplied to the 'cyl-' inder 28,'but insteadthe latter is vented through connection 84, chamber 89, passage 4|,chamber 88 and port 88 to the atmosphere. To raise the plunger 48when'desired, a magnetwinding 58 is arranged in proper relation to theplunger so that upon the supply of current to the magnet winding 58, thesame will be energized and effective to lift the plunger 48 -and',causea reversal of the position of the valves shown in Fig. 2. It will benoted that the pilotmechanism 32 will effect unloading'when the.solenoid or magnet 88 is de-energized, .and loading when it isenergized, and so that energization and de-energization of the magnet'58 may becaused to take place in proper dependence upon the receiverpressure, means is provided including a pressure responsive switch 82having herein a pressure responsive element 58 subjected at one side 'toreceiver pressure through -a connection 84 and having its other sideadapted to transmit motion to a switch element 88 through a suitablemechanism, herein a bell crank mechanism 56.

Before further describing the circuits of the illustrative embodiment ofthe invention I may state that I provide a starting switch mechanism,generally designated START, and a stopping switch mechanism, generallydesignated STOP, and that with the starting switch mechanism there isherein associated a time delay device 88 whose purpose and structurewill later be de-- scribed. It may be noted also that at 8| there isprovided an auxiliary switch element of the so-called interlock typewhose purpose will shortly be apparent, this switch element being movedto closed position concurrently with the closure oi the starting switch1.

- Now it will be noted that a conductor 82 leads from-the motor lead M?to one end of the magnet winding 88, and that the other end 01 thismagnetw'indingis connected by a conductor 88 to one of the stationarycontact elements 64 asso; ciated with the receiver-pressure-operatedswitch element 88. ,The other stationary contact 88, with which theswitch element 55 coacts, is connected by a conductor 88 to a contact 81forming one of an upper pair (the other numbercd 88) of contacts of theSTART switch apparatus. A movable contact member 88 in its upperposition is adapted to connect the contacts 81, 88. Contact 88 isconnected by a conductor 18 and a conductor H to line L and bya-conductor 12 is connected both to a conductor 18 leading to astationary contact 14 with which iishing a circuit later more fullydescribed, and also by a conductor 18 to a lower stationary contact 18forming one of a pair (the other element is numbered 11) of lowercontacts of the START switch mechanism. Contact element 11 is connectedby a conductor 18 to an upper contact 19 engageable in its closedposition by the switch element 88 of the STOP switch mechanism. Theother stationary contact of the STOP switch mechanism, designated 8|, isconnected by a conductor 82 to the pivot end of the interlock switch 8i.From theconductor 18 there branches a conductor 83 which leads to oneend of the main operating coil l for the starting switch, and the otherend of said operating magnet coil is connected by a conductor 84 to astationary contact 85 with which switch element l8 'coacts. The otherstationary contact 86 with which switch element l6 contacts is connectedby a conductor 81 toline L. A spring 88 normally maintains the STOPswitch element 88 in contact with stationary contacts 19, 8|. A spring89 normally maintains the switch element 69 in contact with the contacts81, 88. A manually operablev plunger 98 may be moved downward throughmeans including the dashpot mechanism 68 against the pressure of thespring 89 with substantially no retardation, and cause 69 to connectcontact elements 16, 11. The dashpot device 68 provides a slow,retarded, upward movement of the switch element 69 with a substantialtime delay after pressure is removed from the plunger 98 before contactwill be broken between the element 69 and the contacts 18 and 11. Theby-pass 9i permits a sharp upward movement of the switch element 68 justas it approaches the point of leaving contact with the stationary switchelements 18, 11, so that arcing is minimized.

Now, the mode of operation of this device will be readily understood,but as a preliminary, it should be said that the time delay created bythe dashpot device 88 will be made such that the motor I will have hadabundant time to bring the compressor 2 up to full operating speedbefore, even following an immediate release of pressure from the plunger98, the switch element 89 will be able to leave contact with thestationary switch elements 16 and 11.

To start the compressor, the operator will depress the plunger 98 andmove the contact ele* ment 69 into contact with the elements 18 and 11.This will establish a circuit from line L through conductor 81, switch86, I8, 85,conductor 84, magnet winding l5, conductor 83, conductor 18,switch 11, 89, 18, and conductor 15, conductor 12 and conductor 1| toline L This will energize the magnet winding l5, and'the plunger l4 willclose the switch 1 and move the interlock switch element 8| into contactwith the stationary contact element 14. Closure of the switch element 6|will result in a circuit from line B through conductor 81, switch 88,I8, 85, conductor 84, magnet" l5, conductor 83, the stop switch 19, 88,8!, conductor 82, switch element 8i, stationary switch contact 14, andconductors 18, 12, 1| to line L this being in parallel to the circuitoriginally established; and accordingly, even through the spring 89,after a few seconds of initial supply of motor starting current, movesthe contact 89 to break the circuit between contacts 16, 11, there willbe maintained an energizationbi the solenoid l8 and a maintenance of theswitch 1 in closed position. It will be noted that this holding circuitincludes the STOP switch mechanism, and that by depressing the member 88out of contact with the contacts 18, 8t, the solenoid l5 can be readilyde-energized and the motor caused to stop by the opening of the startingswitch 1'. Itwill be noted, moreover, that upon an overload of themotor, the

excessive flow 01' current through either coil 0 or or both. will beeffective to cause opening of the switch I, and this also will break.the

circuit through the main motor switch operating interlock switch element8| also moves to open position, and so manual closure of the startingswitch mechanism, including the downward movement of the plunger 98 andthe switch eiement 88, the latter into contact with the contacts T6 andTI, is necessary to restart the motor.

It will be observed that the depressing o! the element 69 out ofengagement with the contacts 61 and 68 prevents the establishment of acircult, which would otherwise have been made on closure of the switchelement ii, if the pressure was low enough tocause switch 58 to close,from line L throughswitch element 12, motor lead M", conductor 62,magnet winding 50, conductor 88, contact 64, switch element 55. contact65,

conductor 66, contact 81, switch element 69, contact 68, conductor 18,conductor H, and line L Accordingly, energization of the winding 58 isimpossible until switch element 68 moves back a into contact with thecontacts 61, 68, and therefore, because of the time delay device,loading will be impossible until the motor has come up to speed, thetime lapse occasioned by the dashpot mechanism 68 giving time enough forthis to result. Obviously, the 'dashpot 80 could be omitted if it weredesired to hold the element 69 manually out of contact with the contacts81, 68 long enough to permit the motor to come up to speed beforeestablishment of the circuit by the switch parts 61, 68 and 89.. Ofcourse, if the switch isopenpas will be the case if the receiverpressure is greater than the predetermined minimum for which the switch.mechanism 82 is set, the compressor will not load, even on the upwardmovement to the position shown in Fig. l of the contact element 69.

It will be appreciated that I have provided an exceedingly simple andvery effective arrangement for maintaining a compressor unloaded duringthe time when the latter is comingup to speed. Moreover, with a minimumofmechanism, this function is accomplished, and the compressor systemenabled to operate under the load-and-unload system of output control.

While I have in this application specifically described one embodimentwhich the invention may assume in practice, it will be understood thatthis embodiment of the same is shown for purposes of illustration andthat the invention may be modified and embodied in various other formswithout. departing ,irom its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is z I 1. Incombination, a pump having unloading means, pressure responsivecontrolling means for said unloading means, a driving motor for saidpump, motor controlling means includinga member movable from onepredetermined position to ,another to start said motor and out of thelat- ,a predetermined position to make said unloading means inoperative,a driving motor for said pump, and means for starting said motorconnected with said member and moving'the latter onto! saidpredetermined position when actuated to start said motor, and means formaintaining said motor in operation when said member is returned to saidpredetermined position.

3. In combination, a pump having unloading means, an electric controlfor the latter including a pressure responsive switch, a solenoid, and afurther switch, both said pressure responsive switch and said furtherswitch having to be closed to effect loading, a pump driving motorhaving a starting'switch, and controlling means 'for the latternecessitating opening of said second mentioned switch during starting ofthe pump driving motor,

4. In combination, apump having unloading means, an electric control forthe latter including a pressure responsive switch, a solenoid, and afurther switch, both said pressure responsive switch and said furtherswitch having to be closed to effect loading, apump driving motor havingan electrically actuated starting switch, an operating magnet for thelatter having a control circuit established by said further switch whenthelatter is moved to open the circuit of said unloadng meanscontrol,'and means for maintaining said magnet energized independentiyof said further switch, whereby reclosing of said further switch aftermotor starting is possible. v

5. In combination, a pump having unloading means, an electric controlfor the latter including a pressure responsive switch, a solenoid, and

a further swi ch, both said pressure responsive switch and said furtherswitch having to be closed to eflect loading, means for automaticallymov- 'means operable to open said parallel circuit and deenergize saidoperating magnet.

6. In combination, a pump having unloading means, a driving motor forsaid pump, a starting switch for said motor having an operating magnet,controlling means for said unloading means including an operatingsolenoid energized to effect loading, separate circuits for.said magnetand solenoid, a switch element operative in different positions thereofto establish said separate circuits, and means operable by said magnetfor maintaining a holding circuit through said magnet.

"'7. In combination, a pump having unloading means, a driving motor forsaid pump, .a starting switch for said motor having an operating magnet,controlling means for said unloading means including an operatingsolenoid energized to effect loading, separate circuits for said magnetand solenoid respectively, a switch element operative in differentpositions thereof to form an element of said separate circuits, meansfor automatically restoring said switch element, when moved'therefrom,to a position to form an ele-, ment, of the solenoid controllingcircuit, means operative on closure of said starting switch due I tomovement of said switch element into said magnet circuit to create aholding circuit around said switch element for said magnet, and meansoperable to open said holding circuit and deenergize said magnet.

8. In combination, a pump having unloading means, a driving motor forsaid pump, a starting -switch for said motor having an operating magnet,controlling means for said unloading means including an operatingsolenoid energized to effect loading, separate circuits forsald magnetand solenoid respectively, the circuit for said solenoid containing apump-discharge-pressure responsive switch, a switch element operative indiflerent positions thereof to form an element of said separatecircuits, means for automatically restoring said switch element, whenmoved therefrom, to a position to form an element of the solenoidcontrolling circuit, means operative on closure of said starting switchdue to movement of said switch element into said magnet circuit tocreate a holding circuit around said switch element for said magnet, andmeans operable to open said holding circuit and deenergize said magnet.v

9. In combination, a pump having unloading means, a driving motor forsaidpump, a starting switch for said motor having an operating magnet,controlling means for said unloading means including an operatingsolenoid energized to effect loading, separate circuits for said magnetand solenoid respectively, a switch element operative in diflerentpositions "thereof to form an element of said separate circuits, meansfor automatically restoring, after a predetermined time lapse, saidswitch element, when moved therefrom, to a position to form an elementof the solenoid controlling circuit, and means operative on closure orsaid starting switch due to movement of said switch element into saidmagnet circuit to create a holding circuit'around said switch elementfor said magnet.

10. In combination, a pump having unloading means, a driving motor forsaid pump, a starting switch for said motor having an operating magnet,controlling means i'or said unloading means including an operatingsolenoid energized to effect loading, separate circuits for "said magnetand solenoid respectively, the latter circuit containing a pumpdischarge pressure responsive switch, a switch element operative indifierent positions thereof to establish said separate circuits, meansfor normally maintaining said switch element in the solenoid circuit andfor automatically'returning it thereto after movement to establish themagnet circuit, and means operative on energization of said magnet dueto movement of said switch element into said magnet circuit to shuntsaid switch element in the magnet circuit and maintain said magnetcircuit closed after said switch element has been returned to saidsolenoid circuit.

11. In combination, a pump havingunloading means, a driving motor forsaid pump, a starting switch for said motor having an operating ,mag-

net, controlling means for said unloading means including an operatingsolenoid energized to efiectloading, separate circuits (or. said magnetand solenoid respectively, the latter circuit con taining a pumpdischarge pressure responsive switch, a switch element operative indifferent positions thereof to establish said separate cirment toestablish the magnet circuit, means operative on energization of saidmagnet due to movement of said switch element into said magnet circuitto shunt said switch element in the magnet circuit, and dashpot meansretarding movement of said switch element out of the magnet circuit.

12. In combination, a pump having unloading means, a driving motor forsaid pump, motor starting and stopping means including a member movableto a predetermined position to eflect motor starting and thereaftermovable out of said position without stopping said motor, pressureresponsive controlling means for said unloading means requiring thepositioning of said member out of said predetermined position thereof toenable loading, and controlling means for the positioning of saidmember.

13. In combination, a pump having unloading means, pressure responsivecontrolling means for said unloading means including an operating systemin which the operating medium is controlled both in response to pumpdischarge pressure and through the position of a control element, adriving motor for said pump, and controlling means for said drivingmotor requiring the positioning of said control element in'a position toprecludepump loading to effect motor starting, but not subsequentthereto for continued motor operation, and means for controlling theposition of said controlling element.

14. In combination, a pump having unloadin means, pressure responsivecontrolling means for said unloading means including an operating systemin which the operating medium is controlled both in response to pumpdischarge pressure and through the position of a control element, adriving motor for said pump, and controlling means for said drivingmotor requiring the positioning of said control element ina position topreclude pump loading to effect motor starting, but not subsequentthereto forcontinued motor operation, and means for controlling theposition of said controlling element automatically, normally maintainingthe same ina position enabling the effecting of loading.

15. In combination, a pump having unloading means, a controlling systemfor the latter including a pressure responsive element movable tocontrol the flow of an operating medium and a second element alsomovable to control the flow of such operating medium, a pump drivingmotor, and'controlling means for said motor including devices foreffecting motor starting rendered operative on movement of said secondelement to interrupt operating medium flow in said system,-

means for maintaining said motor in operation after starting thereof,independently of the position of said second element, and a furtherelementmovable to effect motor stopping.

JESS M. BARTHOLOMEW.

